Small near-infrared fluorescent proteins developed from cyanobacteriochrome and methods for their engineering

Abstract

This invention provides the nucleic acid molecules encoding novel small monomeric near-infrared fluorescent protein miRFP670nano, variants and derivatives thereof as well as proteins and peptides encoded by these nucleic acids. The invention also relates to derivatives, homologues, or mutants of the specific proteins referenced above as well as fragments of the nucleic acids and the peptides encoded thereby. The invention further relates to host-cells, stable cell lines and transgenic organisms comprising above-referenced nucleic acid molecules. The present invention also refers to methods of making and using small monomeric near-infrared fluorescent proteins derived from cyanobacteriochromes. The presented protein and its derivatives find use in a variety of applications and approaches, including labeling of biomolecules, cells or cell organelles, detecting protein-protein interactions, and generation of genetically encoded fluorescent biosensor.

What is claimed is: 
     
         1 . A method for optical imaging a biological sample comprising exposing a biological sample containing therein an isolated fluorescent miRFP718nano protein, with a sequence of at least 95% identity to SEQ ID NO:4, to an fluorescence excitation wavelength and quantifying a Near Infra-Red (NIR) tissue transparency window fluorescence therefrom so as to image the biological sample. 
     
     
         2 . The method of  claim 1 , wherein the biological sample comprises prokaryotic or eukaryotic cells. 
     
     
         3 . The method of  claim 2 , wherein the cells are live. 
     
     
         4 . The method of  claim 2 , wherein the cells are fixed. 
     
     
         5 . The method of  claim 2 , wherein the cells comprise mammalian cells. 
     
     
         6 . The method of  claim 1 , wherein lamp, laser or other light source excitation is used. 
     
     
         7 . The method of  claim 1 , wherein the biological sample comprises biological tissue. 
     
     
         8 . The method of  claim 1 , wherein the biological sample comprises cells or biological tissue within living animal.